This invention is a new and distinct cultivar of apple tree. It was discovered by applicants in August, 1979, at West Lafayette, Ind., in the course of an attempt to develop improved apple trees with high fruit quality and resistance to Venturia inaequalis (Cke.) Wint., the causal agent for the apple scab disease. The tree is a seedling of known parentage planted in 1975 in Block F of the Hinsley Breeding Orchard at the Horticultural Farm of the Purdue University Agricultural Experiment Station, Lafayette, Ind. In the above orchard, its position was Row 20, Tree 42, having the description PRI 2845-1 in the breeding records.
The present new cultivar, which is designated as COOP 23, is a seedling produced from crossing the seedling PRI 1018-101 as the seed parent and the seedling N.J. 50 as the pollen parent in 1973 at Urbana, Ill. This new cultivar carries a genetic factor, V.sub.f, inherited from Malus floribunda 821, causing it to be resistant to infection caused by Venturia inaequalis. The presence of this genetic factor has been repeatedly proven by controlled inoculation tests of the seedling in the Purdue greenhouse and by continuous field exposure to a natural population of the organism. The complete pedigree is shown below: ##STR1##
The new cultivar produces a vigorous, spreading tree with good annual crops borne on short spurs. It is field immune to apple scab caused by Venturia inaequalis (Cke.) Wint. and to cedar apple rust caused by Gymnosporangium juniperi-virginianae Schw. It is moderately resistant to powdery mildew caused by Podosphaera leucotricha (Ell. & Ev.) Salm. and to fireblight caused by Erwinia amylovora (Burr.) Winslow.
The tree flowers prior to `McIntosh` and just prior to or at the same time as `Redfree`, which is described in U.S. Plant Pat. No. 4,322. The apple fruit has very good quality that is excellent for the season. The fruit holds texture and quality for at least four weeks during refrigerated storage at 34.degree. F. When picked overripe, the fruit has a tendency to watercore.
After observation, the selection was asexually propagated by grafting on seedling apple roots and on three different apple dwarfing rootstocks. The grafted material has maintained the desired characteristics after propagation.